In August 2013, Jeffrey Wogenstahl received a letter from the Department of Justice informing him that an FBI expert’s hair testimony in his case exceeded the limits of science, and should be discounted.

It seems that Jeff is far from alone.An FBI report published last week, about the cases it has so far investigated, reveals mistakes in 33 of the 35 capital cases (94%) prior to 2000 where FBI hair expert testimony helped to incriminate a defendant at trial. A comparable proportion of non-capital cases was found to have been similarly tainted.

Peter Neufeld, Co-Director of the Innocence Project, sums up the conclusions:“These findings confirm that FBI microscopic hair analysts committed widespread, systematic error, grossly exaggerating the significance of their data under oath with the consequence of unfairly bolstering the prosecutions’ case.”

Amy Hess, Executive Assistant Director, Science and Technology Branch, FBI, seeks to reassure those affected:“… the Department and the FBI are committed to ensuring that affected defendants are notified of past errors and that justice is done in every instance.”

And yet of the 33 death row inmates identified in this report, over 40% have either been executed already or have died while on death row. Was justice done for all of them?

In Jeff’s case the issues of FBI hair testimony go far beyond the flawed scientific analysis of hair: the very discovery of the hair by the FBI agent, Douglas Deedrick, is itself suspicious, since a previous thorough examination (by the Trace Evidence section of the Hamilton County Coroner’s Office) had revealed no hair to be present. In a case where federal Judge Karen Moore referred to ‘the breadth and depth of prosecutorial misconduct that occurred in this case’ the mysterious arrival of the hair must ring alarm bells loud and clear.

Jeff’s case is not the only one where FBI flawed hair testimony is one of many concerns in a capital case. For instance, in the case of Willie Manning in Mississippiwe learn:“The prosecutor’s case relied on testimony from a jailhouse snitch and a woman who wanted to see her own criminal charges disappear…”

When FBI flawed hair testimony is but a small part of the failings in the way capital cases are conducted, the alarm bells should be deafening.